Many advanced communication systems transmit information through a plurality of parallel optical communication channels. The optical communication channels may be defined by a fiber optic ribbon interconnect (or fiber optic cable) formed from a bundle of glass or plastic fibers, each of which is capable of transmitting data independently of the other fibers. Relative to metal wire interconnects, optical fibers have a much greater response, they are less susceptible to interference, and they are much thinner and lighter. Because of these advantageous physical and data transmission properties, efforts have been made to integrate fiber optics into computer system designs. For example, in a local area network, fiber optics may be used to connect a plurality of local computers to centralized equipment, such as servers and printers. In this arrangement, each local computer has an optical transceiver for transmitting and receiving optical information. The optical transceiver may be mounted on a substrate that supports one or more integrated circuits. Typically, each computer includes several substrates that are plugged into the sockets of a common backplane. The backplane may be active (i.e., it includes logic circuitry for performing computing functions) or it may be passive (i.e., it does not contain any logic circuitry). An external network fiber optic cable may be connected to the optical transceiver through a fiber optic connector that is coupled to the backplane.
Fiber optic transceivers typically include a transmitter component and a receiver component. The transmitter component typically includes a laser, a lens assembly, and a circuit for driving the laser. The fiber optic receiver component typically includes a photodiode and a high gain receiver amplifier, which may be operable to perform one or more signal processing functions (e.g., automatic gain control, background current canceling, filtering or demodulation). For one-directional data transfer, a transmitter component is required at the originating end and a receiver component is required at the answering end. For bi-directional communication, a receiver component and a transmitter component are required at both the originating end and the answering end. In some cases, the transmitter circuitry and the receiver circuitry are implemented in a single transceiver integrated circuit (IC). The transceiver IC, photodiode and laser, along with the lenses for the photodiode and the laser are contained within a package that has a size that is sufficiently small to fit within a fiber optic communication device.